In recent years, a substrate processing apparatus is used to perform various treatments on substrates, such as semiconductor wafers. Examples of the substrate processing apparatus include a CMP (Chemical Mechanical Polishing) apparatus for performing polishing treatment on substrates.
The CMP apparatus is provided with, for example, a polishing unit for performing polishing treatment on substrates, a cleaning unit for performing cleaning and drying treatments on substrates, and a load/unload unit for transferring substrates to the polishing unit and receiving substrates cleaning and drying-treated by the cleaning unit. The CMP apparatus is also provided with a transport unit for transporting substrates within the polishing unit, the cleaning unit and the load/unload unit. The CMP apparatus sequentially performs various treatments, including polishing, cleaning and drying, while transporting substrates with the transport unit.
Incidentally, there has been known a technique to detect whether or not abnormality is present in the operation of a substrate processing apparatus, such as a CMP apparatus. For example, recipe data in which procedures or methods related to substrate treatment are defined is stored in a manipulating PC of the substrate processing apparatus. The manipulating PC outputs instructions on substrate treatment based on the recipe data to a sequencer of each unit. The sequencer of each unit controls each component within the unit according to the recipe data output from the manipulating PC, thereby realizing treatment consistent with the recipe data.
Assume here, for example, that the content of recipe data received by the sequencer of a polishing unit from the manipulating PC states “Flow 50 mL of a polishing liquid per unit time.” In this case, the sequencer of the polishing unit controls each component within the polishing unit, so that 50 mL of the polishing liquid flows per unit time. A flow rate sensor for the polishing liquid is disposed in the polishing unit to detect the flow rate of the polishing liquid. The sequencer compares the flow rate of the polishing liquid detected by the flow rate sensor with the flow rate (50 mL) of the recipe data. If, as the result of comparison, there is no difference between the flow rates or if the difference is within a preset range of thresholds, the sequencer determines that no abnormality is present in the substrate processing apparatus (polishing unit).